Used chewing gum is frequently discarded onto floors and other surfaces. Chewing gum is particularly difficult to remove by mechanical means, and it has been found that the best technique for removing it is to apply steam/vapour to it at the same time as applying a mechanical action, such as brushing/abrading. The steam/vapour breaks down the chewing gum deposit, making removal possible. Previous gum removal equipment comprises a small LPG/Propane gas canister which is used to heat up liquid from a reservoir to produce steam, which can then be dispensed from a nozzle onto a chewing gum deposit. More specifically, this technology involves pumping a pre mixed chemical into a 6 mm stainless steel pipe that is coiled and heated by a flame, powered by the LPG/propane gas. This method allowed the metal to reach a temperature hot enough to turn the liquid into instant steam.
More generally, current methods of producing heated liquid or steam are mainly based on providing a heating element in a boiler. The problem with using a boiler-based system is that it is necessary to deal with the changing pressure that is caused by the water expanding to enable steam to be created. This issue causes steam machines to constantly require replacement “o” rings, which are a weak point, and which fail due to the high pressure being created. The pressure may be so strong that an excessive build up would either damage the “o” rings or result in a ruptured boiler. The water that is heated in the boiler chamber is converted to vapour/steam stage then pumped through to a lance to complete a cleaning task. To use a steam-cleaning machine to remove chewing gum, a separate source of chemical would be attached to the machine. This chemical is pumped from a separate chamber and injected into the steam (usually at the end of the lance) to allow the cleaning process to be effective. The boiler/element systems are very slow to heat up as they work on the principle of a kettle coming to the boil to generate vapour/steam. They also require considerable power, as often they are required to heat between 2 and 5 liters of water to allow the operator to have sufficient steam at point of contact/cleaning. Due to traditional steam machines relying on an ever-changing volume of water in the reservoir they cannot maintain a consistent pressure. When the internal pressure changes and the steam pressure changes the machines stop generating steam and the cleaning process must stop to wait for pressure to build sufficiently for vapour/steam to be generated again. Typically this can take 10 minutes to build. The end result is that the operator of the machine has constantly fluctuating periods of waiting for pressure to build, especially on constant fill machines.
It has also been noted by the applicant that the production of hot water or other fluids form a portable source remains problematic for many of the above reasons. Many cleaning processes are undertaken by machines using cold water, sometimes mixed with harsh, environmentally damaging or poisonous chemicals, to undertake the cleaning process. The safety and efficiency of these cleaning processes could be greatly improved if a portable source of water or other cleaning fluid was readily available, the use of a heated fluid potentially reducing the timescale of the cleaning process and the volume of chemicals required.
The provision of hot water in caravans, recreational vehicles, tents and other mobile abodes may also be problematic. The use of a generator or other existing means of providing a supply of hot water may be undesirable in many situations, due to issues of excessive noise, a lack of portability or the absence of an easily accessible power supply. Again, the provision of an instant supply of hot water in an energy efficient way would be of great advantage to the user. Such a solution would be beneficial in both the leisure and commercial fields, for example in supplying hot water for bathing or, alternatively, for the commercial preparation of food or beverages at a location where a traditional power source such as mains electricity or a generator is not available.
Embodiments of the present invention seek to address these problems.